checkermanager.java

《Java网络程序设计.rar》包括三个网络程序的源代码。

package org.impact.stars.control.web.checker;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletContext;

import java.util.Collection;
import java.util.HashMap;

import org.impact.stars.control.web.RequestProcessor;
import org.impact.stars.util.Debug;
import org.impact.stars.control.event.StarsEvent;

import org.impact.stars.control.exceptions.StarsEventException;

/*
 *This class manages all of the access checkers within the web container
 * For each event, it finds or initialise a AccessRule with a data model
 * For each type of event, it finds or initialise a Checker
 * The mapping between event and checker are defined in the JNDI lookup
*/

public class CheckerManager implements java.io.Serializable {

    private RequestProcessor reqpro;
    private HashMap attributeMap;
    private HashMap checkerMap;
    private ServletContext sc;
    
    public CheckerManager()
    { 
    }
    public void init(RequestProcessor reqpro, ServletContext sc) {
        this.reqpro = reqpro;
        this.sc = sc;
        attributeMap = new HashMap();
        checkerMap = new HashMap();
    }

    public String checkEvent(StarsEvent ese) throws StarsEventException{
        Debug.println("CheckerManager: received event= " + ese);
        String eventName = ese.getEventName();
        String permition = "OK";
        if (eventName != null) {
            Debug.println("CheckerManager: processingEvent= " + eventName);
            String checkerName = getCheckerName(eventName);
            Debug.println("CheckerManager: process checker class = " + checkerName);
            ConsistentChecker checker = getChecker(checkerName);
            
            
            if (checker != null) {
                Debug.println("CheckerManager: initialzied " + checkerName);
                // do the magic
                //checker.doStart();
                permition =  checker.getPermition(ese);
                Debug.println("CheckerManager: sucessfully processed :" + eventName);
            }
        }
        return permition;
    }

    private String getCheckerName(String eventName) {
        // the checker JNDI names are set in the web layer JNDI conf.
        // see the web.xml file for list
        Debug.println("CheckerManager: looking up:" + eventName + "<");
        try {
                    InitialContext ic = new InitialContext();
                    return  (String)ic.lookup(eventName+"Checker");
        } catch (javax.naming.NamingException ex) {
                   Debug.println("AccountChecker caught: " + ex);

        }
        return null;

    }


    public void setAttribute(String key, Object value) {
        attributeMap.put(key, value);
    }

    public Object getAttribute(String key) {
        return attributeMap.get(key);
    }

    public RequestProcessor getRequestProcessor() {
        return reqpro;
    }

    public ServletContext getServletContext() {
        return sc;
    }
    
    public void doStart(StarsEvent ese){
        Debug.println("CheckerManager: doStart for event= " + ese);
        String eventName = ese.getEventName();
        if (eventName != null) {
            String checkerName = getCheckerName(eventName);
            ConsistentChecker checker = getChecker(checkerName);
            
            if (checker != null) {
                checker.doStart(ese);
                Debug.println("CheckerManager: sucessfully doStart :" + eventName);
            }
        }
    }
    
    public void doEnd(StarsEvent ese){
        Debug.println("CheckerManager: doEnd for event= " + ese);
        String eventName = ese.getEventName();
        if (eventName != null) {
            String checkerName = getCheckerName(eventName);
            ConsistentChecker checker = getChecker(checkerName);
            
            if (checker != null) {
                checker.doEnd(ese);
                Debug.println("CheckerManager: sucessfully doEnd :" + eventName);
            }
        }
    }
    
    private ConsistentChecker getChecker(String checkerName)
    {
        ConsistentChecker checker = null;
         try {
                 if (checkerMap.get(checkerName) != null) {
                    checker = (ConsistentChecker)checkerMap.get(checkerName);
                 } else {
                     checker = (ConsistentChecker)Class.forName(checkerName).newInstance();
                     checker.init(this, sc);
                     checkerMap.put(checkerName, checker);
                     Debug.println("CheckerManager: loaded checker " + checkerName);
             }
            } catch (Exception ex) {
                Debug.println("CheckerManager: error loading " + checkerName + " :" + ex);
            }        
            return checker;
    }
}